As the eclipse approaches totality, the light in the sky is not the only thing that will change.
Anna Green with the McDonnell Planetarium at the St. Louis Science Center says you will also be able to notice an interesting phenomenon called “shadow bands.”
Similar to the way light moves in a swimming pool, the waves will move and ripple. NASA says this will be visible for several minutes before and after the eclipse, and that it can be explained by “atmospheric turbulence.”
To see this phenomenon, place a large piece of white paper on the ground (light-colored concrete will show the shadow bands, too). Eclipse glasses are not required for viewing shadow bands.